Rear Interior lights stopped working

[2008-T5]

Looking for some help, the rear interior lights no longer come on when rear doors are opened on my 2008 T5 they started off by being intermittent some time on sometimes off, so this is where I'm up to, I moved rear light to second row and that to the rear, all works ok on second row but still not in rear, I'm assuming its a door switch related issue or wiring breakdown as the door open warning icon on dash also does not come on when rear barn doors are open but ok on all other doors, I'm not sure what triggers the interior light but hoping someone can guide me further I'm also guessing that one of the many wires passing through the cable cater door to body work may also have broken through but the all appear ok. Help please